[Buildroot] rootfs hooks okay to use?

[Danomi Manchego]

Arnout.

On Wed, Sep 19, 2012 at 2:19 AM, Arnout Vandecappelle <arnout at mind.be>wrote:
> Any commands to be executed by make should start with a TAB character,
> so make recognizes them as commands.

I don't think so.  If I change the beginning of my both
my TEST_PRE_GEN_HOOK_FIXUP and the ROOTFS_CPIO_ADD_INIT to start with tabs,
the error changes to:

fs/cpio/cpio.mk:35: *** missing separator.  Stop.
make: *** [all] Error 2

On the other hand, the package hooks have no problem with multiple hooks
and no tabs.  For example, this works without any errors:

+define TEST_HOOK_FIXUP1
+ echo "This is a test hook1"
+endef
+
+define TEST_HOOK_FIXUP2
+ echo "This is a test hook2"
+endef
+
+ZLIB_POST_INSTALL_TARGET_HOOKS += TEST_HOOK_FIXUP1
+ZLIB_POST_INSTALL_TARGET_HOOKS += TEST_HOOK_FIXUP2

However, I think I've figured it out the difference.  The rootfs hooks are
iterated by a foreach statement in fs/common.mk in ROOTFS_TARGET_INTERNAL.
 But ROOTFS_TARGET_INTERNAL is actually a template, so the single $ are
evaluated by the $(eval $(call ROOTFS_TARGET,xxxx)).  But if the single $
are replaced by double $, then the foreach evaluation is deferred to later.
 Then, the multiple hooks seem to work.

The specific change is:

 $(BINARIES_DIR)/rootfs.$(1): $(ROOTFS_$(2)_DEPENDENCIES)
        @$(call MESSAGE,"Generating root filesystem image rootfs.$(1)")
-       $(foreach hook,$(ROOTFS_$(2)_PRE_GEN_HOOKS),$(call $(hook))$(sep))
+       $$(foreach hook,$$(ROOTFS_$(2)_PRE_GEN_HOOKS),$$(call
$$(hook))$$(sep))
        rm -f $(FAKEROOT_SCRIPT)

So if the hooks are supposed to be generally available for tacking on more
actions, then I think we need the double $'s ...

Danomi -
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